a long trip (word on shorter trips later), don't get too much into planning at home - just pick, depending on how much time you have, a few places and regions you want to see. What you often don't realise is that after several months on the road you can lack the passion for 14 plus hour bus trips or the money for internal flights to get to every 'attraction'. Equally many regions aren't as connectible on a budget as a world map might make them look.
It's true that the happiest travellers are the most flexible. Hell, if you have the time, why not even try to travel without an ultimate return ticket - or at least make sure dates can be changed with ease. You will soon realise where the tourist trail is (the easiest and most convenient way to see all the sights) and follow it, making modifications where you want. Most itineraries are just that - dots on a map of places people would like to see or things they'd like to do, then joined up by the cheapest most convenient transport options. Maybe your desired route comes from places/regions you'd always wanted to see, are interested in or simply sound romantic/adventurous to you. You'll do a bit of research with guidebooks, the internet and hopeful the list below and add a few more to your list and equally realize which routes are feasible and which are not so, then finally do a bit of tweaking for current events and weather patterns.
Limited to a shorter few week trip? For the record if you are reading this and have weeks not months to travel in, this shouldn't deter you. Sure you need to plan a little more - pick one or two destinations and remember a few internal or regional flights and a little bit more money, lets you cover a lot in a short time-frame. It's not uncommon to see and do more in a few weeks that some long-term 'backpackers' achieve in a month!
However if you are lucky enough to have the time, then pick a couple of regions, say SE Asia or Central America (good starters, loads of options), India/northern Pakistan (as good as it gets and quite a test) and Australia or Europe (Western countries are less exotic, but not less interesting; don't discount them - just budget well!) and plan to spend a few months in each, of course being flexible to stay longer or move on faster. Plain and simple, caprice is a great thing to have.
